<!--$Id: dbenv.so,v 11.13 2006/04/24 17:26:34 bostic Exp $-->
<!--Copyright (c) 1997,2008 Oracle.  All rights reserved.-->
<!--See the file LICENSE for redistribution information.-->
<html>
<head>
<title>Berkeley DB Reference Guide: Release 3.0: the DB_ENV structure</title>
<meta name="description" content="Berkeley DB: An embedded database programmatic toolkit.">
<meta name="keywords" content="embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++">
</head>
<body bgcolor=white>
<table width="100%"><tr valign=top>
<td><b><dl><dt>Berkeley DB Reference Guide:<dd>Upgrading Berkeley DB Applications</dl></b></td>
<td align=right><a href="../upgrade.3.0/func.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../upgrade.3.0/open.html"><img src="../../images/next.gif" alt="Next"></a>
</td></tr></table>
<p align=center><b>Release 3.0: the DB_ENV structure</b></p>
<p>The <a href="../../api_c/env_class.html">DB_ENV</a> structure is now opaque for applications in the Berkeley DB
3.0 release.  Accesses to any fields within that structure by the
application should be replaced with method calls.  The following example
illustrates this using the historic errpfx structure field.  In the Berkeley DB
2.X releases, applications set error prefixes using code similar to the
following:</p>
<blockquote><pre>DB_ENV *dbenv;
<p>
	dbenv-&gt;errpfx = "my prefix";</pre></blockquote>
<p>in the Berkeley DB 3.X releases, this should be done using the
<a href="../../api_c/env_set_errpfx.html">DB_ENV-&gt;set_errpfx</a> method, as follows:</p>
<blockquote><pre>DB_ENV *dbenv;
<p>
	dbenv-&gt;set_errpfx(dbenv, "my prefix");</pre></blockquote>
<p>The following table lists the <a href="../../api_c/env_class.html">DB_ENV</a> fields previously used by
applications and the methods that should now be used to set them.</p>
<table border=1 align=center>
<tr><th><a href="../../api_c/env_class.html">DB_ENV</a> field</th><th>Berkeley DB 3.X method</th></tr>
<tr><td>db_errcall</td><td><a href="../../api_c/env_set_errcall.html">DB_ENV-&gt;set_errcall</a></td></tr>
<tr><td>db_errfile</td><td><a href="../../api_c/env_set_errfile.html">DB_ENV-&gt;set_errfile</a></td></tr>
<tr><td>db_errpfx</td><td><a href="../../api_c/env_set_errpfx.html">DB_ENV-&gt;set_errpfx</a></td></tr>
<tr><td>db_lorder</td><td>This field was removed from the <a href="../../api_c/env_class.html">DB_ENV</a> structure in the Berkeley DB
3.0 release as no application should have ever used it.  Any code using
it should be evaluated for potential bugs.</td></tr>
<tr><td>db_paniccall</td><td>DB_ENV-&gt;set_paniccall</td></tr>
<tr><td>db_verbose</td><td><a href="../../api_c/env_set_verbose.html">DB_ENV-&gt;set_verbose</a>
<p>Note: the db_verbose field was a simple boolean toggle, the
<a href="../../api_c/env_set_verbose.html">DB_ENV-&gt;set_verbose</a> method takes arguments that specify exactly
which verbose messages are desired.</p></td></tr>
<tr><td>lg_max</td><td><a href="../../api_c/env_set_lg_max.html">DB_ENV-&gt;set_lg_max</a></td></tr>
<tr><td>lk_conflicts</td><td><a href="../../api_c/env_set_lk_conflicts.html">DB_ENV-&gt;set_lk_conflicts</a></td></tr>
<tr><td>lk_detect</td><td><a href="../../api_c/env_set_lk_detect.html">DB_ENV-&gt;set_lk_detect</a></td></tr>
<tr><td>lk_max</td><td>dbenv-&gt;set_lk_max</td></tr>
<tr><td>lk_modes</td><td><a href="../../api_c/env_set_lk_conflicts.html">DB_ENV-&gt;set_lk_conflicts</a></td></tr>
<tr><td>mp_mmapsize</td><td><a href="../../api_c/env_set_mp_mmapsize.html">DB_ENV-&gt;set_mp_mmapsize</a></td></tr>
<tr><td>mp_size</td><td><a href="../../api_c/env_set_cachesize.html">DB_ENV-&gt;set_cachesize</a>
<p>Note: the <a href="../../api_c/env_set_cachesize.html">DB_ENV-&gt;set_cachesize</a> function takes additional arguments.
Setting both the second argument (the number of GB in the pool) and the
last argument (the number of memory pools to create) to 0 will result in
behavior that is backward-compatible with previous Berkeley DB releases.</p></td></tr>
<tr><td>tx_info</td><td>This field was used by applications as an argument to the transaction
subsystem functions.  As those functions take references to a
<a href="../../api_c/env_class.html">DB_ENV</a> structure as arguments in the Berkeley DB 3.0 release, it should
no longer be used by any application.</td></tr>
<tr><td>tx_max</td><td><a href="../../api_c/env_set_tx_max.html">DB_ENV-&gt;set_tx_max</a></td></tr>
<tr><td>tx_recover</td><td>dbenv-&gt;set_tx_recover</td></tr>
</table>
<table width="100%"><tr><td><br></td><td align=right><a href="../upgrade.3.0/func.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../toc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../upgrade.3.0/open.html"><img src="../../images/next.gif" alt="Next"></a>
</td></tr></table>
<p><font size=1>Copyright (c) 1996,2008 Oracle.  All rights reserved.</font>
</body>
</html>
